The invention relates to a teleconferencing device wherein a pair of such devices enables two persons located at a distance from one another to communicate with one another so that each one can both see and hear the other in much the same manner as if they were face to face in the same room.
It is important that direct eye-to-eye contact is made between the two persons, and accordingly, it is important that when a user is viewing an image along an optical path from a remote teleconferencing device, the image of the user transmitted to the remote device be sensed along that same optical path. It is often desired to transmit an image of an item to be viewed in addition to the image of a person, and accordingly, it is desirable to provide means to do so in an economic and unobtrusive manner.
U.S. Pat. No. 3,755,623 discloses a combined television camera and television receiver unit for transmitting images of either a person or a document to be viewed. In the patented construction, mechanical means must be moved from one position to another in order to change from the transmission of an image of a person to the transmission of an image of a document and vice versa. Such movable mechanical means are relatively expensive to manufacture and are subject to failure during operation.
A further problem with a device such as shown in the aforementioned U.S. patent is that the CRT utilized therein may be oriented such that undesirable electromagnetic radiation such as radio frequency and X-ray emissions are directed at the user.